黑木耳多糖的提取工艺优化及抗氧化活性研究

以黑木耳为原料,研究超声波辅助提取黑木耳中多糖的工艺条件和体外抗氧化活性。以多糖提取率为评价指标,通过单因素试验和正交试验探讨料液比、超声时间、超声温度、超声功率对黑木耳多糖提取率的影响,并探索其抗氧化活性。结果表明:超声波辅助优化黑木耳多糖的最佳提取工艺条件为料液比1∶40(g/m L)、超声时间20 min、超声温度50℃、超声功率100 W,在此条件下,黑木耳多糖平均提取率为9.69%。     

鸢尾叶异黄酮超声波辅助提取工艺优化及抗氧化活性研究

采用超声波辅助法提取鸢尾(Iris tectorum Maxim)叶中异黄酮,运用正交试验优化其提取工艺,并运用自由基清除试验考察鸢尾叶异黄酮的抗氧化活性。研究结果表明,影响异黄酮提取率大小的因素依次为:乙醇体积分数超声功率超声时间料液比,异黄酮提取的最佳工艺条件为:乙醇85%,料液比1︰25(g/mL),超声功率90W,超声时间50 min。此条件下鸢尾叶中异黄酮的得率为15.62 mg/g。此外,鸢尾叶异黄酮对DPPH及羟自由基均显示显著清除活性,表明其具有较强抗氧化活性。     

超声辅助同时提取迷迭香鼠尾草酸和迷迭香酸

以迷迭香干叶为原料,采用超声辅助的方法从迷迭香中提取迷迭香酸、鼠尾草酸等有效成分,考察了超声提取时间、乙醇体积分数、料液比和超声功率等因素对提取工艺的影响,并通过响应面法进行工艺优化,得到了提取过程优化的工艺条件:乙醇体积分数72.29%、料液比1∶10.05、超声时间51.27 min、超声功率200.55W。拟合得到的模型较好的符合实际。     

海南柠檬皮多糖的提取工艺及体外抗氧化活性研究

目的探索柠檬皮中多糖的超声波提取工艺条件和体外抗氧化活性。方法以海南万宁柠檬皮为原料,通过单因素试验和四因素三水平正交试验研究料液比、超声时间、超声温度、超声功率对柠檬皮多糖提取率的影响,并采用铁离子还原法研究其体外抗氧化活性。结果最佳提取工艺条件是:料液比1:40(g/ml)、超声时间40 min、超声温度50℃、超声功率300 W,柠檬皮多糖平均提取率为10.29%。其体外抗氧化活性随多糖质量浓度的增大呈线性增强。结论该工艺稳定、可行,适合海南柠檬皮多糖的提取,且柠檬皮多糖有较强抗氧化活性。     

超声波辅助提取南瓜籽油及其脂肪酸组成研究

采用超声波辅助提取南瓜籽油,并用单因素试验和正交试验筛选最佳提取条件。结果表明：超声波辅助提取南瓜籽油的最佳工艺条件为料液比1:8(g/mL)、超声时间20min、超声功率90W、超声温度30℃,在此条件下油脂提取率高达94.22%,各因素对提取率的影响依次为料液比、超声时间、超声功率和超声温度。气相色谱分析南瓜籽油表明,南瓜籽油中主要含有5 种脂肪酸,分别是棕榈酸、油酸、硬脂酸、亚油酸和亚麻酸。     

蒲公英叶多糖超声波细胞粉碎辅助提取工艺优化及体外抗氧化活性

利用超声波细胞粉碎技术辅助提取蒲公英叶多糖,并采用响应面法对其提取工艺进行优化。研究超声功率、料液比、提取时间、温度对蒲公英叶多糖提取率的影响,在单因素试验的基础上进行响应面试验并对蒲公英叶多糖的抗氧化能力进行测定。结果表明,蒲公英叶多糖的最佳提取工艺为超声功率197 W、料液比1∶15（g/mL）、提取时间25 min,此工艺下多糖提取率为5.346%。蒲公英叶多糖具有一定的抗氧化活性,其对DPPH 自由基、羟自由基、超氧阴离子自由基的IC50 值分别为34.62、12.16、0.98 mg/mL。     

番石榴叶黄酮的微波提取及其抗氧化作用研究

以番石榴叶为原料,采用微波技术优化番石榴叶中黄酮类物质的提取工艺,并研究番石榴叶黄酮对油脂的抗氧化作用。试验结果表明,番石榴叶中黄酮类物质的最佳微波萃取工艺参数是:微波提取时间10 min,微波功率400 W,料液比1∶30,乙醇体积分数50%。在此提取条件下,番石榴叶中总黄酮的提取率为134.46 mg/g。番石榴叶黄酮提取物对植物油脂具有一定的抗氧化作用,可作为植物油脂的天然抗氧化剂。     

正交试验法优化超声提取黄米中多糖

通过单因素试验研究料液比、超声功率、提取时间、提取温度对黄米中多糖提取率的影响,再利用正交试验法优化最佳提取工艺条件,得出最佳提取工艺参数:料液比1∶23 (g/mL)、超声功率100 W、提取温度70℃、提取时间40 min,该条件下黄米中多糖的提取率为7.35%。     

迷迭香总黄酮的提取工艺

研究迷迭香中总黄酮的最佳提取工艺。采用单因素试验和正交试验考察乙醇浓度、料液比、提取时间和提取温度对总黄酮提取率的影响。结果表明,迷迭香总黄酮最佳提取工艺条件为：乙醇浓度50%,料液比1∶20（g/mL）,提取时间4 h,提取温度90℃,在此条件下总黄酮提取率达6.31%。     

超声波辅助提取油莎豆油脂工艺研究

以油莎豆为原料,研究利用超声波辅助提取油莎豆油脂的工艺条件,通过单因素试验和正交试验优化了超声波辅助提取油莎豆油脂的工艺条件。结果表明：超声波辅助提取油莎豆油脂工艺的最佳条件是超声温度60℃、料液比1∶18、超声时间20min,在此条件下油脂提取率高达92.57%。各因素对油莎豆油脂提取率的影响依次为超声温度、料液比和超声时间。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.